US 20040119155A1 corresponding to JP-A-2004-200464 discloses a metal wiring plate for electrically connecting an electronic device to other device through solder. The metal wiring plate is a cluster of wiring portions arranged and held in a predetermined wiring pattern. The wiring portion has a soldering portion to which an electronic device is soldered. When melted solder applied to the soldering portion spreads to areas outside the soldering portion, a suitable solder fillet is not formed at the soldering portion. As a result, the electronic component cannot be surely soldered to the metal wiring plate. To prevent this program, the areas outside the soldering portion are coated with solder resist. However, the solder resist coating needs a printing process, which increases manufacturing cost of the metal wiring plate.